You're kinda on the right track..."betterment of said species" in this case is due to overpopulation, hence men who would choose whether or not to have a child with a woman that would be a surrogate.
If evolution was trying to take the homosexual "gene" out of the population, that would require two things: 1) homosexuality to be genetic and hereditary, which, unless my grandparents and/or parents are gay, it doesn't seem to be; and 2) that with this hereditary trait would come infertility. We can still procreate if we so choose, and I have a lot of friends with kids of their own that aren't gay. But again, the second point is irrelevant because it hasn't been proven that it's hereditary, so technically, and I stand corrected, it's not technically evolution until (by definition) it is inherited, which could potentially happen.
What has been proven is that the development of male-to-male (evil, disgusting fag sinners) or female-to-female (fucking hot, total turn on, lesbians are awesome) attraction occurs due to elevated hormone levels produced by the mother and fetus during the development of sexual differentiation during pregnancy (usually around the 8th week). So therefore, it's not a DNA thing, it's a genetic variation that could eventually manifest itself into a permanent inheritable DNA change. But again, evolution to remove homosexuality would denote that all homosexuals would be genetically sterile, so two individual genetic mutations, one for actual homosexuality and one linking infertility to that homosexual gene, would be needed in order to say that evolution is causing a removal of homosexuals.
Is it preventable? Possibly, but who would want that? If we got rid of the gays the world would be REALLY boring...horrible fashion, no dance music, no theater, no Anderson Cooper, no Magneto, no True Blood, no Glee (ok, bad example), no Olympic swimming or diving events, no Clive Davis (yes, that's accurate...the founder of Bad Boy and LaFace is gay), no David Geffen (so Dreamworks, Geffen Records, etc), oh yeah, and Tim Cook, the CEO of Apple.
So yeah, is it that big of a deal to you? Why are you so against it? What if your kid was gay? Are you gonna be so insensitive and selfish that you wouldn't accept it?[/Q
This is your opinion, I like mine better. Also how long( years) do you feel you will be able to take it in the ass before you will be required to wear depends to keep from shitting your pants when you sneeze.